A municipal sewage efficient flocculation and sedimentation treatment method

Abstract

The application belongs to the technical field of sewage treatment, and particularly relates to a municipal sewage efficient flocculation and sedimentation treatment method, which comprises the following steps: introducing sewage into a flocculation tank, adding a flocculant into the flocculation tank and stirring, flocculating pollutants in the sewage to form sludge; sewage with the sludge overflowing into a sedimentation tank, separating and settling in the sedimentation tank to separate the sludge from clear water, the upper clear water overflowing into a clear water tank, and the sludge settling in the sedimentation tank; pumping the clear water in the clear water tank for standby; discharging the mixture of water and sludge in the sedimentation tank and filtering, and recycling the filtered clear water and sludge; the treatment method separates the upper clear water from the sludge through an overflow mode, and realizes efficient treatment of the sewage.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a method for efficient flocculation and sedimentation treatment of municipal wastewater. Background Technology

[0002] If pollutants in municipal wastewater are discharged directly without effective treatment, they will pollute water bodies, soil, and other environmental components. Flocculation and sedimentation are crucial processes in municipal wastewater treatment, and their efficiency directly determines the effluent quality and purification efficiency of subsequent treatment processes.

[0003] The current mainstream method for treating municipal wastewater involves adding flocculants to the wastewater before discharging it into a sedimentation tank for separation. However, direct discharge of wastewater into the sedimentation tank can easily impact the sludge in the water, causing the settled sludge to float back to the surface, or even break down and damage it, reducing sedimentation efficiency and affecting the cleanliness of the separated water. Therefore, how to efficiently treat the continuously increasing volume of municipal wastewater is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for efficient flocculation and sedimentation treatment of municipal wastewater, which separates the upper layer of clear water from the sludge through overflow, thereby achieving efficient wastewater treatment.

[0005] The specific technical solution adopted in this invention is as follows:

[0006] A method for efficient flocculation and sedimentation treatment of municipal wastewater includes the following steps:

[0007] S1. Introduce wastewater into the flocculation tank, add flocculant and stir. The pollutants in the wastewater flocculate to form sludge.

[0008] S2. Wastewater containing sludge overflows into the sedimentation tank. After sedimentation and separation in the sedimentation tank, the sludge and clear water are separated into layers. The upper layer of clear water overflows into the clear water tank, while the sludge settles in the sedimentation tank.

[0009] S3. Drain the clean water from the clean water tank for later use;

[0010] S4. Discharge the mixture of water and sludge in the sedimentation tank and filter it to recover the filtered clean water and sludge separately.

[0011] The aforementioned treatment method relies on a flocculation and sedimentation system, which includes a frame and a flocculation tank, a sedimentation tank, and a clear water tank arranged sequentially on the frame along the water flow direction. The inlet side of the sedimentation tank is connected to the flocculation tank via a first overflow port, and the outlet side of the sedimentation tank is connected to the clear water tank via a second overflow port. The outlet end of the first overflow port is connected to a first guide plate and a second guide plate forming a water passage. The first guide plate is located below the second guide plate, and a baffle plate is suspended downward at the lower end of the second guide plate. The baffle plate is spaced apart from the side wall of the outlet side of the sedimentation tank. A third guide plate is inclinedly arranged on the side wall of the outlet side of the sedimentation tank. The third guide plate and the second guide plate form an overflow channel that is larger at the top and smaller at the bottom. The upper end of the overflow channel forms a second overflow port.

[0012] Both the first and second guide plates are corrugated plates, and the length direction of the crests of each corrugated plate is inclined downward.

[0013] The second guide plate has a trough that is a variable depth trough, with the depth at the upper end of the trough being less than the depth at the lower end, and the opening of the trough facing the third guide plate.

[0014] The lower end of the second guide plate is provided with a notch, and a sludge sliding channel is formed between the notch and the baffle plate.

[0015] The flocculation tank also has a buffer chamber on the effluent side. The sedimentation tank is connected to the buffer chamber via a first overflow port. The buffer chamber is connected to the flocculation tank via a third overflow port. A buffer plate is suspended inside the buffer chamber, and the buffer chamber forms a U-shaped channel for water flow with the help of the buffer plate.

[0016] The bottom of the buffer chamber is provided with a first drain outlet. The first drain outlet is opened at the same time as the first overflow outlet overflows. The water outlet velocity of the first drain outlet is less than the water outlet velocity of the third overflow outlet. A filter screen is provided below the first drain outlet.

[0017] The frame is also equipped with a mesh belt conveyor, a water collection trough, and a sludge scraper. The water collection trough is located below the mesh belt conveyor, and the sludge scraper is located at the output end of the mesh belt conveyor. The sludge scraper contacts the mesh belt of the mesh belt conveyor to form a sludge scraping structure. A second sewage outlet is provided on the sedimentation tank, which is located above the mesh belt conveyor.

[0018] While the second overflow port overflows, the second drain port is opened, and the water flow rate of the second drain port is less than that of the first overflow port.

[0019] The beneficial effects of this invention are:

[0020] This invention involves adding flocculants to wastewater and mixing them to allow the flocculants to capture pollutant particles and form sludge. The sludge settles and separates from the clear water, and the upper layer of clear water is separated from the sludge through overflow, thus achieving efficient wastewater treatment.

[0021] The treatment method relies on a flocculation and sedimentation system. The cross-sectional area of ​​the overflow channel in the sedimentation tank, which is wider at the top and narrower at the bottom, gradually increases with the height. This slows down the flow of water in the sedimentation tank, prolonging the sedimentation time for sludge and weakening the water's entrainment of the sludge. This facilitates the sludge's downward settling and its descent along the third guide plate, further reducing the sludge content in the overflow water and improving the cleanliness of the water flowing into the clear water tank. This ensures the recycling of the clear water in the clear water tank.

[0022] The effluent side of the flocculation tank also has a buffer chamber, in which the sewage flows steadily, improving the sludge settling effect and reducing the amount of sludge carried in the water overflowing from the first overflow outlet into the settling tank, thus improving the sludge settling effect.

[0023] The mesh belt conveyor is located below the buffer chamber and sedimentation tank. The sludge settled at the bottom of the buffer chamber and sedimentation tank is discharged onto the mesh belt of the mesh belt conveyor. The mesh belt filters the mixed clean water in the sludge, and the clean water falls into the water collection tank below the mesh belt conveyor. The sludge is intercepted on the mesh belt and passes through the scraper roller with the mesh belt. The scraper roller scrapes off the sludge on the mesh belt, allowing the mesh belt to repeat the filtration work. The buffer chamber and sedimentation tank can continuously output the sludge inside without stopping the machine for cleaning, thus achieving continuous and efficient treatment of wastewater with added flocculants. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the flocculation and sedimentation system of the present invention;

[0025] Figure 2 for Figure 1 A magnified view of part A in the middle;

[0026] Figure 3 This is a schematic diagram of the second guide vane.

[0027] Figure 4 This is a schematic diagram of the structure of a mesh belt conveyor;

[0028] In the attached diagram, 1 is the frame, 2 is the flocculation tank, 3 is the sedimentation tank, 4 is the clear water tank, 5 is the buffer chamber, 6 is the first overflow port, 7 is the second overflow port, 8 is the first guide plate, 9 is the second guide plate, 901 is the trough, 902 is the notch, 10 is the baffle plate, 1001 is the reversing protrusion, 11 is the third guide plate, 12 is the buffer plate, 13 is the first sewage outlet, 14 is the mesh belt conveyor, 15 is the water collection tank, 16 is the sludge scraper, 17 is the second sewage outlet, and 18 is the third overflow port. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0030] In a specific embodiment, the present invention relates to a method for efficient flocculation and sedimentation treatment of municipal wastewater, comprising the following steps:

[0031] S1. Introduce wastewater into flocculation tank 2, add flocculant into flocculation tank 2 and stir. Stirring makes the flocculant and wastewater fully mixed, which facilitates the flocculant to capture pollutant particles and cause the pollutant particles to aggregate and form sludge.

[0032] S2. Wastewater containing sludge overflows into sedimentation tank 3. After sedimentation and separation in sedimentation tank 3, the sludge and clear water are separated into layers. The upper layer of clear water overflows into clear water tank 4, and the sludge settles in sedimentation tank 3, thus completing the separation of sludge and clear water. The overflow method reduces the disturbance of wastewater to the settled sludge, reduces the sludge content in the upper layer of clear water, and improves sedimentation efficiency.

[0033] S3. Drain the clean water from the clean water tank 4 for later use;

[0034] S4. Discharge the mixture of water and sludge in sedimentation tank 3 and filter it to recover the filtered clean water and sludge separately.

[0035] like Figure 1 , Figure 2 As shown, this treatment method relies on a flocculation and sedimentation system. The flocculation and sedimentation system includes a frame 1, and a flocculation tank 2, a sedimentation tank 3, and a clear water tank 4 arranged sequentially along the water flow direction on the frame 1. The inlet side of the sedimentation tank 3 is connected to the flocculation tank 2 via a first overflow port 6, and the outlet side of the sedimentation tank 3 is connected to the clear water tank 4 via a second overflow port 7. A first guide plate 8 and a second guide plate 9 are connected to the outlet end of the first overflow port 6. The first guide plate 8 and the second guide plate 9 are spaced apart and both are inclined, forming a water passage connecting to the first overflow port 6. The first guide plate 8 is located below the second guide plate 9. The flocculation tank 2 contains sludge... Wastewater enters the sedimentation tank 3 through the first overflow port 6, and the water passage guides the water flow to flow smoothly downwards. A baffle plate 10 is suspended downwards at the lower end of the second guide plate 9. The baffle plate 10 is spaced apart from the side wall of the sedimentation tank 3 on the outlet side. A third guide plate 11 is inclinedly installed at the upper end of the side wall of the sedimentation tank 3 on the outlet side. The third guide plate 11 and the second guide plate 9 form an overflow channel that is larger at the top and smaller at the bottom. The upper end of the overflow channel forms a second overflow port 7. The baffle plate 10 reverses and intercepts the water flow in the water passage, so that the water inlet direction and water outlet direction of the sedimentation tank 3 are arranged in a detour, so as to prevent the water flowing into the sedimentation tank 3 from the first overflow port 6 from directly entering the overflow channel and to prevent the clear water overflowing in the overflow channel from being mixed with too much sludge.

[0036] The cross-sectional area of ​​the overflow channel, which is wider at the top and narrower at the bottom, gradually increases with the height. This slows down the flow of water in the sedimentation tank 3 during the overflow process, extending the settling time for sludge and weakening the water flow's entrainment of the sludge. This facilitates the sludge's downward settling and its descent along the third guide plate 11, further reducing the sludge content in the overflowing clear water and improving the cleanliness of the water overflowing into the clear water tank 4. This provides a guarantee for the recycling of the clear water in the clear water tank 4.

[0037] Both the first guide plate 8 and the second guide plate 9 are corrugated plates, with the length direction of each corrugated plate inclined downwards. The water overflowing from the first overflow port 6 flows into the water passage. The water flow is dispersed into multiple corrugated channels along the corrugated plates. The inclined corrugated plates guide the water flow to flow smoothly downwards, avoiding direct impact of sewage on the sludge that has settled at the bottom of the sedimentation tank 3, preventing the sludge from being disturbed and floating, improving the stratification effect of sludge and clean water, and helping to improve the cleanliness of the clean water overflowing from the second overflow port 7.

[0038] like Figure 2 , Figure 3 As shown, the trough 901 of the second guide plate 9 is a variable depth trough, with the depth of the upper end of the trough 901 being less than the depth of its lower end. The opening direction of the trough 901 faces the third guide plate 11. During the overflow of clear water, as the speed gradually decreases in the overflow channel, the sludge carried in the clear water sinks downwards. The sludge that falls on the second guide plate 9 slides down to the bottom of the trough 901. The sludge slides down along the trough 901 and accelerates its descent as the trough 901 gradually deepens.

[0039] The lower end of the second guide plate 9 has a notch 902. The notch 902 and the baffle plate 10 form a sludge sliding channel. During the sliding process, the sludge falls into the inlet side of the sedimentation tank 3 along the notch at the lower end of the trough 901 and is carried by the water flow of the water passage and moves quickly downwards. The sludge leaves the second guide plate 9.

[0040] Furthermore, the upper end of the baffle plate 10 is folded over and covers the second guide plate 9. The upper end of the baffle plate 10 overlaps with the lower end of the second guide plate 9 near the second overflow port 7. The covering height is lower than the overflow height of the second overflow port 7. As the water level of the clear water layer rises, the sludge that settles on the second guide plate 9 slides down along the trough 901 of the second guide plate 9. The baffle plate 10 blocks the sludge that slides down the lower end of the trough 901. In addition, the lower end of the baffle plate 10 is also provided with a reversing protrusion 1001 facing the side where the first overflow port 6 is located. The upper surface of 1 is inclined downward, and the upper surface of the reversing protrusion 1001 and the notch 902 form a reversing channel for sludge sliding down the trough 901. The reversing protrusion 1001 guides the sludge sliding down the trough 901 to the side away from the overflow channel, reducing the interference between clean water and sludge and improving the cleanliness of the overflow water. On the other hand, the reversing protrusion 1001, together with the upper end of the baffle plate 10, can also reduce the disturbance of the water flow output from the first overflow port 6 to the sludge settled in the sedimentation tank 3, further preventing the clean water from being contaminated by sludge.

[0041] The effluent side of the flocculation tank 2 also has a buffer chamber 5. The sedimentation tank 3 is connected to the buffer chamber 5 via the first overflow port 6. The buffer chamber 5 is connected to the flocculation tank 2 via the third overflow port 18. The water in the flocculation tank 2 enters the buffer chamber 5 through the third overflow port 18. The sewage is not stirred or disturbed in the buffer chamber 5. The sewage flows steadily in the buffer chamber 5, which improves the sedimentation effect of sludge and reduces the amount of sludge carried in the water overflowing from the first overflow port 6 into the sedimentation tank 3, thereby improving the sedimentation effect of sludge. A buffer plate 12 is suspended inside the buffer chamber 5. The buffer chamber 5 forms a U-shaped channel for water flow with the help of the buffer plate 12. The sewage flowing out of the flocculation tank 2 cannot directly enter the sedimentation tank 3 in a horizontal straight direction. Instead, it flows through the U-shaped channel that turns downward and overflows upward, forcibly changing the direction of water flow, prolonging the flow path and residence time of water in the buffer chamber 5, reducing the disturbance of water flow to the sludge settling at the bottom of the buffer chamber 5, improving the sludge settling effect and the sludge-water stratification effect, and improving the cleanliness of the water overflowing from the first overflow port 6.

[0042] The bottom of the buffer chamber 5 is provided with a first drain outlet 13. The first overflow outlet 6 opens the first drain outlet 13 at the same time as it overflows. The water flow rate of the first drain outlet 13 is less than that of the third overflow outlet 18. A filter screen is provided below the first drain outlet 13. The U-shaped channel design makes the bottom of the buffer chamber 5 form a stable sludge settling zone. The opening of the first drain outlet 13 can accurately discharge the sludge at the bottom of the buffer chamber 5, reduce the amount of sludge at the bottom of the buffer chamber 5, and further avoid disturbing the sludge at the bottom when the water flows into the buffer chamber 5. At the same time, it realizes the continuous buffering and overflow operation of the buffer chamber 5.

[0043] like Figure 1 , Figure 4As shown, the frame 1 is also equipped with a mesh belt conveyor 14, a water collection tank 15, and a sludge scraper 16. The water collection tank 15 is located below the mesh belt conveyor 14, and the sludge scraper 16 is located at the output end of the mesh belt conveyor 14. The sludge scraper 16 contacts the mesh belt of the mesh belt conveyor 14 to form a sludge scraping structure. The sedimentation tank 3 is equipped with a second sewage outlet 17, which is located above the mesh belt conveyor 14. The second sewage outlet 17 is opened at the same time as the second overflow outlet 7 overflows. The water discharge rate of the second sewage outlet 17 is less than the water discharge rate of the first overflow outlet 6. While the second sewage outlet 17 discharges sewage, it ensures that the clear water in the upper layer of the sedimentation tank 3 continues to overflow along the second overflow outlet 7.

[0044] The filter screen installed below the first discharge port 13 is the mesh belt on the mesh belt conveyor 14. The operation of the mesh belt conveyor 14 causes the mesh belt to move, and the sludge settled at the bottom of the buffer chamber 5 and the bottom of the sedimentation tank 3 is discharged through the first discharge port 13 and the second discharge port 17. The mesh belt filters the mixed clean water in the sludge, and the clean water falls into the water collection tank 15 below the mesh belt conveyor 14. The sludge is intercepted on the mesh belt and passes through the scraper roller 16 with the mesh belt. The scraper roller 16 is equipped with a scraper or brush, and the scraper roller 16 scrapes off the sludge on the mesh belt, so that the mesh belt can repeat the filtration work. The buffer chamber 5 and the sedimentation tank 3 can continuously output the internal sludge without stopping the machine for cleaning, thereby realizing the continuous treatment of wastewater with added flocculants.

Claims

1. A method for efficient flocculation and sedimentation treatment of municipal wastewater, characterized in that, Includes the following steps: S1. Introduce wastewater into flocculation tank (2), add flocculant into flocculation tank (2) and stir. The pollutants in the wastewater flocculate to form sludge. S2. Wastewater containing sludge overflows into sedimentation tank (3). After sedimentation and separation in sedimentation tank (3), the sludge and clear water are separated into layers. The upper layer of clear water overflows into clear water tank (4), and the sludge settles in sedimentation tank (3). S3. Drain the clean water from the clean water tank (4) for later use; S4. Discharge the mixture of water and sludge in the sedimentation tank (3) and filter it to recover the filtered water and sludge respectively.

2. The method for efficient flocculation and sedimentation treatment of municipal wastewater according to claim 1, characterized in that: The treatment method relies on a flocculation and sedimentation system, which includes a frame (1) and a flocculation tank (2), a sedimentation tank (3), and a clear water tank (4) arranged sequentially on the frame (1) along the water flow direction. The inlet side of the sedimentation tank (3) is connected to the flocculation tank (2) via a first overflow port (6), and the outlet side of the sedimentation tank (3) is connected to the clear water tank (4) via a second overflow port (7). The outlet end of the first overflow port (6) is connected to a first guide plate (8) forming a water passage. The second guide plate (9) is located below the first guide plate (8). A baffle plate (10) is suspended downward at the lower end of the second guide plate (9). The baffle plate (10) is spaced apart from the side wall of the sedimentation tank (3) on the effluent side. A third guide plate (11) is inclinedly arranged on the side wall of the sedimentation tank (3). The third guide plate (11) and the second guide plate (9) form an overflow channel that is larger at the top and smaller at the bottom. The upper end of the overflow channel forms a second overflow port (7).

3. The method for efficient flocculation and sedimentation treatment of municipal wastewater according to claim 2, characterized in that: The first guide plate (8) and the second guide plate (9) are both corrugated plates, and the length direction of the crests of each corrugated plate is inclined downward.

4. The method for efficient flocculation and sedimentation treatment of municipal wastewater according to claim 3, characterized in that: The second guide plate (9) has a trough (901) that is a variable depth trough. The depth of the upper end of the trough (901) is less than the depth of the lower end, and the opening direction of the trough (901) is towards the third guide plate (11).

5. The method for efficient flocculation and sedimentation treatment of municipal wastewater according to claim 4, characterized in that: The lower end of the second guide plate (9) is provided with a notch (902), and a sludge sliding channel is formed between the notch (902) and the baffle plate (10).

6. The method for efficient flocculation and sedimentation treatment of municipal wastewater according to claim 4, characterized in that: The flocculation tank (2) also has a buffer chamber (5) on the effluent side. The sedimentation tank (3) is connected to the buffer chamber (5) via the first overflow port (6). The buffer chamber (5) is connected to the flocculation tank (2) via the third overflow port (18). A buffer plate (12) is suspended inside the buffer chamber (5). The buffer chamber (5) forms a U-shaped channel for water flow with the help of the buffer plate (12).

7. The method for efficient flocculation and sedimentation treatment of municipal wastewater according to claim 6, characterized in that: The buffer chamber (5) is provided with a first drain outlet (13) at the bottom. The first overflow outlet (6) opens the first drain outlet (13) at the same time as it overflows. The water flow rate of the first drain outlet (13) is less than that of the third overflow outlet (18). A filter screen is provided below the first drain outlet (13).

8. The method for efficient flocculation and sedimentation treatment of municipal wastewater according to claim 2, characterized in that: The frame (1) is also equipped with a mesh belt conveyor (14), a water collection tank (15) and a sludge scraper (16). The water collection tank (15) is located below the mesh belt conveyor (14), and the sludge scraper (16) is located at the output end of the mesh belt conveyor (14). The sludge scraper (16) contacts the mesh belt of the mesh belt conveyor (14) to form a sludge scraping structure. The sedimentation tank (3) is equipped with a second sewage outlet (17), which is located above the mesh belt conveyor (14).

9. The method for efficient flocculation and sedimentation treatment of municipal wastewater according to claim 8, characterized in that: While the second overflow port (7) overflows, the second drain port (17) is opened. The water flow rate of the second drain port (17) is less than that of the first overflow port (6).

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